On 2015.11.05 at 21:52 +0100, David Brown wrote: > There has been some discussions going on in the comp.lang.c newsgroup > about how far compilers are allowed to go regarding optimisation using > their knowledge of undefined behaviour (i.e., if a piece of code has > undefined behaviour, the compiler can assume that the user does not care > about the result in that case, and can therefore do whatever it wants in > order to generate faster code). The compiler just assumes that undefined behavior will not happen and optimizes accordingly. Now that -fsanitize=undefined is available this shouldn't be a big issue anymore. For more details I recommend John Regehr's excellent blog entries on this topic, e.g.: http://blog.regehr.org/archives/1234 -- Markus
